Power transfer system

Abstract

The frequency generated by a high-frequency high-voltage generator is set to a higher one of the frequencies of two coupled modes which take place when a resonance circuit of a power transmission device and that of a power reception device are coupled to each other. For this reason, charge generated on an active electrode of the power transmission device and that generated on an active electrode of the power reception device have the same polarity, while an electric potential of a passive electrode of the power transmission device and that of a passive electrode of the power reception device have the same polarity. When the passive electrode of the power transmission device is connected to the ground, the electric potential of the passive electrode is zero V. Therefore, the electric potential of the passive electrode of the power reception device is substantially zero V.

The invention claimed is: 
     
       1. A power transfer system comprising:
 a power transmission device including a power transmission device side active electrode, a power transmission device side passive electrode, and a high-frequency high-voltage generator circuit configured to generate a high voltage of high frequency to the power transmission device side active electrode and the power transmission device side passive electrode; and 
 a power reception device including a power reception device side active electrode opposed to the power transmission device side active electrode, a power reception device side passive electrode, and a high-frequency high-voltage load circuit connected between the power reception device side active electrode and the power reception device side passive electrode, 
 wherein the high-frequency high-voltage generator circuit generates the high voltage with the high frequency being a frequency such that a phase difference between a first phase of a first electric potential difference between the power transmission device side active electrode and the power transmission device side passive electrode and a second phase of a second electric potential difference between the power reception device side active electrode and the power reception device side passive electrode has an absolute value of not less than zero degrees and less than 90 degrees. 
 
     
     
       2. The power transfer system according to  claim 1 , wherein a first resonance frequency of a power transmission circuit comprising the power transmission device side active electrode, the power transmission device side passive electrode and the high-frequency high-voltage generator circuit is substantially equal to a second resonance frequency of a power reception circuit comprising the power reception device side active electrode, the power reception device side passive electrode and the high-frequency high-voltage load circuit, and
 wherein the high-frequency high-voltage generator circuit generates the high voltage at a higher frequency of frequencies of two coupled modes that occur when the power transmission device and the power reception device are coupled to each other. 
 
     
     
       3. The power transfer system according to  claim 1 , wherein the power transmission device side passive electrode has an electric potential substantially equal to a ground potential. 
     
     
       4. The power transfer system according to  claim 1 , wherein the power transmission device side passive electrode is larger in size than the power transmission device side active electrode. 
     
     
       5. The power transfer system according to  claim 1 , wherein the power reception device side passive electrode is larger in size than the power reception device side active electrode. 
     
     
       6. The power transfer system according to  claim 1 , wherein the power transmission device side passive electrode is arranged so as to oppose the power reception device side passive electrode when the power transmission device side active electrode is opposed to the power reception device side active electrode. 
     
     
       7. The power transfer system according to  claim 1 , wherein the power transmission device and the power reception device each include an LC resonance circuit. 
     
     
       8. The power transfer system according to  claim 1 , wherein the power transmission device includes a series-connected LC resonance circuit and the power reception device includes a parallel-connected LC resonance circuit. 
     
     
       9. The power transfer system according to  claim 1 , wherein the power transmission device includes a first parallel-connected LC resonance circuit and the power reception device includes a second parallel-connected LC resonance circuit. 
     
     
       10. The power transfer system according to  claim 1 , wherein the power transmission device and the power reception device each include a series-connected LC resonance circuit. 
     
     
       11. The power transfer system according to  claim 7 , wherein the power reception device further includes an inductor inductively coupled to an inductor of the LC resonance circuit. 
     
     
       12. The power transfer system according to  claim 1 , wherein the power transmission device further includes a step-up transformer connected to the high-frequency high-voltage generator circuit. 
     
     
       13. The power transfer system according to  claim 12 , wherein the high-frequency high-voltage load circuit includes a rectifier smoothing circuit and a low voltage circuit portion.